import pandas as pd
df=pd.DataFrame([['a',2,5],
['b',3,6],
['c',5,8],
['a',7,3],
['c',6,9]],columns=['A','B','C'])
df.groupby(['A'])['B'].max()
A
a 7
b 3
c 6
Name: B, dtype: int64
df.groupby(['A'])['B'].sum()
A
a 9
b 3
c 11
Name: B, dtype: int64
df.groupby(['A'])['B'].mean()A
a 4.5
b 3.0
c 5.5
Name: B, dtype: float64